Electrical and thermal analysis of an asynchronous machine for application in wind energy generation

 

 

O I Okoro^I; E Chikuni^II

^IUniversity of Nigeria, Nsukka
^IIPolytechnic of Namibia, Windhoek, Namibia

 

 

---

ABSTRACT

The electromagnetic (electrical) and mechanical design of an Asynchronous machine for application in wind energy generation depends on the knowledge of heat transfer within the various parts of the machine. Unfortunately, the analysis of thermal effect in Asynchronous motors is usually more complex, more non-linear and more difficult than the electromagnetic behaviour. This paper therefore, sets out to investigate the effect of coupling the electrical model with the thermal model of the machine. The results of the analysis show that the proposed coupled model is capable of predicting the stator phase currents, rotor bar temperature, stator windings temperature, heat losses, rotor speed and electromagnetic torque of the test machine under dynamic conditions and at rated load operation. The analysis finds application in wind energy generation especially when modified and applied to synchronous generators. By so doing, the prediction of critical temperatures of machine parts can be achieved prior to machine operation.

Keywords: asynchronous machine, electrical model, thermal model, coupling, wind energy, dynamic behaviour

---

 

 

Full text available only in pdf format.

 

Acknowledgement

The first author wishes to thank Prof. Dr.-Ing. B. Weidemann for his useful discussion on the subject and to DAAD for their financial assistance during the research work at the University of Kassel, Germany.

 

References

Bastos, J.P; Cabriera, M.F.R.R; Sadowski, Ν and Arruda, S.R.: Ά thermal analysis of induction motors using a weak coupled modelling', IEEE Transactions on Magnetics, Vol. 33 No. 2, March 1997, pp. 1714 1717.         [ Links ]

Gerald, C.F.: Applied Numerical Analysis, Addison- Wesley publishing company, London, 1978.         [ Links ]

Griffith, J.W; McCoy, R.M and Sharma, D.K: 'Induction motor squirrel cage rotor winding thermal analysis', IEEE Transactions on Energy Conversion, Vol. EC-1 No.3, September 1986, pp. 22-25.         [ Links ]

Jordan, H.E: 'Digital computer analysis of induction machines in dynamic systems', IEEE Transactions on Power Apparatus and Systems, Vol. PAS-86 No.6, June 1967, pp.722-728.         [ Links ]

Klamt, J.: Berechnung und Bemessung elektrischer Maschinen, Springer Verlag, 1962.         [ Links ]

Krause P.C and Thomas C.H: 'Simulation of symmetrical induction machinery'; Transactions IEEE, Vol. PAS- 84 No. 11, 1965, pp. 1038-1053.         [ Links ]

Krause, P.C.: Analysis of Electric Machinery, New York, McGraw-Hill, 1986.         [ Links ]

Kylander, G: Thermal modelling of small cage induction motors, Doctor of Technology Thesis, Chalmers University of Technology, Gothenburg, Sweden, 1995.         [ Links ]

Levy, W; Landy, C.F. and McCulloch, M.D.: 'Improved models for the simulation of deep bar induction motors', IEEE Transactions on Energy Conversion, Vol. 5 No. 2, June 1990, pp. 393-400.         [ Links ]

Mellor, P.H; Roberts, D and Turner, D.R; 'Lumped parameter thermal model for electrical machines of TEFC design', IEE proc. Β Vol. 135 No. 5, 1995 pp.205-218.         [ Links ]

Momoh, J.A. and Xu, Kaili: 'Evaluation of Renewable energy options for national electricity needs', Proceedings of the 6^th International conference on power systems operation and planning, 22-26 May 2005, pp. 13-21.         [ Links ]

Okoro O.I: Dynamic and thermal modelling of induction machine with non-linear effects, Kassel University Press, Kassel, September 2002.         [ Links ]

Okoro, O.I.: 'Computer Simulation of Induction Machine coupled to a mechanical load', Nigerian Journal of Engineering Management, Vol. 4 No. 4, 2003, pp. 28-38.         [ Links ]

Paalman, E. and Morgan, R.: 'Electricity supply to a remote village using grid-connected wind generators', Proceedings of the 13^th conference on the Domestic Use of Energy, 29-31 March 2005, pp.131-136.         [ Links ]

Perdikaris, G.A.: Computer Controlled systems: Theory and Applications, Kluwer Academic Publishers, Netherlands, 1996.         [ Links ]

The MATLAB User's guide, The Mathworks Inc, Natick, 1991.         [ Links ]

 

 

Received 26 April 2007
Revised 31 January 2008